Drill and blast excavation forecasting using 3D laser scanning

Abstract

The application of 3D laser scanning technology in tunnelling has gained increasing significance in recent years. Laser scanning is an innovative holistic approach for data acquisition in tunnelling regarding the geometrical parameters. It is a distance‐based imaging technique for three‐dimensional and high‐resolution illustration (3D point cloud) of the surrounding rock that can be applied at various times to provide a variety of visualization and analysis possibilities. A new approach deals with excavation forecasting by linking the acquisition of the 3D geometry of previously excavated rounds with the geological documentation of the tunnel face. This approach enables the gathering of information about the expected overbreak or underprofile of subsequent excavation in similar rock conditions. Using this information, an optimization of the borehole positions (especially of the peripheral boreholes) can achieve the best possible excavation profile. This approach offers an improvement of excavation performance and saving potential with regard to excavation quantity and shotcrete consumption. The uniform excavation shape and consistent shotcrete thickness improve tunnel stability and finally increases the service life the tunnel structure.

Sensing and monitoring in tunnels testing and monitoring methods for the assessment of tunnels

“…In this way, every scan can be localized in the project or global coordinate system and be compared with one another. Thus, verification of displacement with an accuracy of 1 to a few mm is possible …”

Digitalisierung im Infrastrukturbau – Baubetriebliche Entwicklungen

“…The blast is detonated by sensor-controlled detonation. The best possible precision between under-and over-profile is ensured by modern control and information technologies, which should ensure the precision demanded in the contract [11,12].…”

“…scaling of the face) before muck clearance are determined. Laser scanning can gain the following information [12]: -Production of excavation profiles, -Documentation of the overprofile, -Calculation of the shotcrete thickness, -Documentation of support measures.…”

“…B. Ablauten der Ortsbrust) vor dem Schuttervorgang werden bestimmt. Durch den Laserscan können folgende Informationen gewonnen werden [12]:…”

The Brenner Base Tunnel – geological, construction and logistical challenges and innovations at half time

“…Systematic checks of the specified oversize, recording of the geological overbreak and documentation of the asbuilt state are carried out with a laser tunnel scanner and/or digital photogrammetry and are intended to ensure the geometry and thus the quality. Systematic tunnel scan images of each round enable optimisation of the blasting pattern [12] and continuous determination of the thick ness of the shotcrete lining and its geometry. The evalua tion is performed by importing point clouds from the scanned images of the excavated geometry and the shot crete surfaces into a 3DCAD model.…”